The present invention relates to analyzing samples of substances taken from an industrial fabrication process.
In order to check that a process is running properly, it is common practice to take samples at regular intervals of a product in the course of fabrication, and to analyze the samples by some suitable method: for example by chromatography, in particular gas chromatography; by colorimetry; or by measuring electrical conductivity. It is possible with these methods to analyze the presence of various components in the product and also to determine their relative concentrations. A knowledge of these facts can be used to control the running of an industrial process so as to continuously adjust its operating conditions with a high degree of accuracy as a function of reaction progress and in such a manner as to obtain a finished product whose characteristics are constant or are subject to little variation.
In the past, such analysis methods have required each sample to be individually analyzed by qualified operators, each making use of one or more independently operating analysis stations.
It will readily be understood that this method of proceeding, although capable in some cases of obtaining analysis results which are at least useable even if not particularly reliable or accurate, is unwieldly and expensive when a continuous industrial process is being run, in particular because of the relatively slow response time inherent to this method of analysis.
In order to remedy this drawback, proposals have been made to provide an installation comprising an analysis assembly having a plurality of analysis stations of determined characteristics (e.g. various chromatographs), with the analysis stations receiving substance for analysis from a device for transferring samples which arrive in a predetermined order as a function of the particular stations for which they are intended.
Although such an installation provides a certain saving in time, it is still not entirely satisfactory by virtue of the need to pre-program the operation of the assembly, and consequently of the need to perform an initial sorting operation on the samples, placing them in ordered storage slots as a function of the predetermined availability of the analysis stations and in accordance with a correspondence table.
In this type of installation, sample substance for analysis is taken from storage station. The sample taken is then transferred and injected into the appropriate analysis station. This transfer operation frequently allows the substance to evaporate partially, and as a result the analysis does not accurately reflect the sample as originally taken from the industrial process.
One proposal for improving this situation has been to label each flask containing a sample of product with an identification code that can be read and used to cause an analysis station to perform the appropriate analysis process.
This proposal has the advantage of providing a solution which is closer to the needs of industry which, in modern industrial fabrication processes, are typified by the requirement for rapid, automatic and reliable processing of all types of sample using a process for each sample which is appropriate thereto and regardless of the order in which samples are presented.
However, this proposal is still not entirely satisfactory since it does not take account of a possible priority order attributed to the samples to be processed when, for understandable reasons of speed, capacity, reliability, and/or cost, the analysis installation being used is common to a plurality of fabrication processes taking place simultaneously, which processes therefore provide collections of samples that arrive in random manner but that are to be analyzed according to specific methods and while satisfying relative priorities which may vary.
Preferred implementations of the present invention seek to meet the above requirements by proposing a novel method and novel apparatus for automatically taking and analyzing samples under present day industrial conditions.